Guiding Factors of Evolution
From the point of view of supporters of "opportunistic evolution", there are no regular and organizing tendencies behind the various directions of evolutionary changes, except for the action of natural selection, which organizes the variability of organisms only in the direction of the development of adaptations to changes in the environment. From this point of view, the main directions of the evolutionary process (aro-, epecto-, allo- and catagenesis), in fact, are equivalent - in the sense that each of them is only a means to achieve the success of a given group of organisms in the struggle for existence (such a point A.N. Severtsov also adhered to the view).
Indeed, among the driving factors of evolution, only natural selection has an organizing effect on the variability of organisms, and at the same time selection is really devoid of a certain direction, which was emphasized by Charles Darwin. But Darwin also pointed out the factor that determines the specific directions of evolutionary transformations: "The nature of conditions in determining each given change has a subordinate significance in comparison with the nature of the organism itself." Although the evolution of organisms is based on probabilistic processes - the emergence of mutations (the phenotypic manifestation of which is inadequate to the changes in external conditions that caused them) and natural selection, the "nature of the organism", that is, the organizational basis of living systems, limits the manifestations of randomness in evolution to certain limits. In other words, the systemic organization channels phylogenesis, i.e. directs evolutionary transformations in certain channels, and for any particular group of organisms, the choice of possible paths of evolution is limited. The concept of hard-coded (nomogenetic) evolution is based on the absolutization of the guiding role in the evolutionary process of the organizational basis of living systems, while the concept of opportunistic evolution is based on the absolutization of the guiding role of natural selection. Truth is usually to be found somewhere between extreme points of view.
The specific directions of phylogenetic transformations of various groups of organisms are determined by the interaction of the forces of natural selection and the historically established organization of these groups. Therefore, we can talk about two categories guiding factors of evolution: extraorganic (selection forces) and organismic.
For any given species, the peculiarities of its organization create preconditions (pre-adaptation) for the development of certain adaptations and impede the development of others, "allow" some directions of evolutionary transformations and "forbid" other directions. The combination of these positive and negative characteristics of the evolutionary capabilities of this group is designated as organismic guiding factors of evolution. These factors can be divided (somewhat conditionally) into three categories, in accordance with the level of their manifestation in ontogenesis:
1) genetic,
2) morphogenetic,
3) morphophysiological (morphofunctional).
The action of the first two categories of organismic guiding factors is fully manifested already at the level of microevolution. As already noted (Part II, Ch. 1), each genotype and gene pool of each species is characterized by a certain set of possible ("allowed") mutations, or a spectrum of mutational variability, which is limited not only qualitatively, but also quantitatively, that is, a certain the frequency of occurrence of each type of mutation. At the same time, some mutations turn out to be impossible (forbidden) for a given genotype (and gene pool) - for example, blue and green eye colors for fruit flies or blue flower colors for rosaceous plants. The reason for this is the lack of appropriate biochemical prerequisites in the genotype.
Since the gene pools of related species retain sets of homologous genes inherited from a common ancestor, homologous mutations naturally appear in them (see p. 65). Homologous mutations can serve as the basis for parallel evolutionary changes in closely related species that have recently diverged from a common ancestor. However, in the course of time, different-quality (non-homologous) mutations inevitably accumulate in the gene pools of isolated species; this occurs even under the action of stabilizing selection, when the phenotypic effect of mutations in structural genes is blocked by modifier genes. In different species, whose gene pools have been isolated from each other for a long time, homologous structures of the phenotype are preserved, but their genetic control can differ significantly (and even almost completely). Therefore, the parallel evolution of phyletic lineages that have long diverged from a common ancestor (to the level of different genera, families, etc.) is based not so much on homologous mutations as on the action of two other categories of organismic guiding factors.
(Homology is the similarity of structures based on the commonality of their origin. The ratio of homologous structures belonging to different levels of hierarchical organization of biological systems (including genetic and phenotypic homology) is complex and ambiguous).
Some mutations that are biochemically possible for a given genotype (i.e., allowed at the genetic level), ultimately, however, lead to fatal consequences for the developing organism in the form of morphogenetic disorders (lethal mutations, for example, the morphogenetic consequences of mutations in congenital hydrocephalus in house mouse, see p. 325). Each ontogeny can be changed only in a certain way, that is, within the framework of the corresponding spectrum of possible ontogenetic changes. This further narrows the choice of possible directions of evolutionary transformations.
Finally, there are also morphophysiological evolutionary restrictions and prohibitions, the action of which (as well as the corresponding preadaptation) is fully manifested only on the scale of macroevolution, being one of the specific reasons for its directed nature. They are due to a variety of relationships within morphophysiological systems and between these systems in the phenotype of adult organisms. At the same time, mutations and restructuring of ontogeny, which could lead to corresponding changes in the phenotype, are themselves quite possible, and mutant individuals with a certain frequency can appear in populations of this species. However, the resulting changes in the phenotype (even seemingly having a high adaptive value!) Cannot be used to form new adaptations due to their inconsistency with the morphophysiological organization of this species. Such transformations remain impracticable until the corresponding morphophysiological restrictions are lifted.
So, for example, keratinization can develop in the epidermis of amphibians - there are the necessary biochemical prerequisites for this, and there are no morphogenetic prohibitions for this process. Indeed, local keratinization of the epidermis develops in the integument of some amphibian species (for example, horny claws in clawed frogs or in male clawed newts, horny "teeth" in tadpoles of many species of tailless amphibians). However, it turned out to be impossible for amphibians to form on this basis such keratinization of the integument that could effectively protect the body from dehydration in the air and in salt water bodies, as in reptiles, birds and mammals. This is due to the need for amphibians to maintain a constantly moist surface of the skin, which is used as an additional organ of gas exchange, primarily to remove carbon dioxide from the body (see below for more details).
Morphophysiological evolutionary restrictions and prohibitions are due to the need for harmonious restructuring of body systems, integrated adaptively (i.e. included in the general adaptive complex), functionally, or at least topographically. In phylogeny, the effect of such restrictions is manifested in the form of various coordinations (i.e., phylogenetic correlations) between various structures and systems of the organism. Topographic coordination refers to the simplest conjugate evolutionary changes in organs closely related spatially. For example, an increase in the size of the eyes is impossible without corresponding rearrangements of the skull, changes in the position of muscles, blood vessels and nerves in the orbit and temporal region. Dynamic coordination is the phylogenetic relationship of organs connected with each other in ontogeny by functional correlations. An example of evolutionary constraints based on such coordination is the impossibility of strengthening any muscle group without a corresponding strengthening of the skeletal structures and some other muscle groups, since this would make the coordinated work of the musculoskeletal system mechanically imperfect. So, there is no point in the development of powerful femoral muscles while maintaining the weaker leg muscles, since the latter cannot effectively transfer the contraction force of the former to the substrate. At the same time, the muscles of the lower leg cannot significantly increase in animals adapted to fast running, since this would significantly increase the moment of inertia of the limb. This evolutionary limitation requires the development of a characteristic design of the limbs in fast-running animals, in which the bulk of the muscles are located in the proximal sections (shoulder, thigh), and the force of their contraction is transmitted to the support through the thin and light distal sections (forearm, lower leg, foot) through the system tendons.
I.I.Shmalgauzen also distinguished the so-called biological coordination, which is understood as conjugated changes in organs and individual structures that are not directly related to each other by any correlations in ontogenesis, but are included in the general adaptive complex (for example, evolutionary relationships between the structure of the masticatory muscles , teeth, jaw bones and jaw joints, due to a certain way of nutrition). Coordinated evolutionary changes in these heterogeneous structures are determined by natural selection.
Key features and cascading interactions
In an integral organism, various organs and structures are interconnected by various forms of correlations and coordination, and the chains of these interconnections are intricately intertwined with each other. At the same time, some kind of bottlenecks arise in the organization of many groups of organisms - such key morphofunctional features of the organization, which through a cascade of various correlative and coordination relationships have a decisive influence on the functioning of many dependent systems of the body.
In the coordination cascade of interconnected systems, the state of each subsequent level is determined by the previous one, starting from key, or limiting system... Transformations of the key system can have both negative ("prohibitive") and positive ("permissive") effects on evolutionary changes. dependent body systems... In the first case, they cause the emergence of morphophysiological evolutionary prohibitions that prevent the development of certain adaptations and directions of evolutionary transformations, in the second, on the contrary, they remove such prohibitions and restrictions that existed before.
The cascade morphophysiological relationships in the organization of amphibians, determined by the characteristics of their respiratory system, are very interesting. Amphibians use a pressure pump for ventilation of the lungs, formed by the hypoglossal apparatus and its muscles and which is a modified branchial pump of the ancestors of terrestrial vertebrates - cross-finned fish. The imperfection of this breathing pump, located in front of the lungs (in the absence of effective mechanisms that can change the volume of the pulmonary sacs themselves), leads to incomplete emptying of the lungs during exhalation, to the preservation of a certain amount of stagnant air there, to mixing of exhaust and fresh air in the oropharyngeal cavity (Fig. 108). As a result, although the lungs in amphibians can provide the body with sufficient oxygen, they are unable to effectively free it from carbon dioxide. This made it necessary to develop in amphibians an additional way of removing carbon dioxide - through the skin. As we have already mentioned, the respiratory function of the skin requires constant moisture of the integument due to the activity of the skin glands and inhibits intense keratinization of the epidermis. This sharply limits the range of habitats accessible to amphibians both on land (where amphibians are active, as a rule, only at high humidity) and in water: due to the high permeability of the integument, amphibians cannot perform effective osmoregulation in the hypertonic environment of salt water bodies (where they are the body becomes dehydrated, losing moisture through the integument), and the sea is inaccessible to amphibians. On the contrary, in the hypotonic environment of fresh water bodies through the integument, an excess amount of water is continuously supplied to the body of amphibians, which must be removed from the body by the excretory organs. This prevents the development of water saving devices in the excretory system of amphibians. The circulatory system of amphibians must serve two organs of gas exchange - the lungs and the skin, and the blood from them flows to the heart through different main vessels (the pulmonary vein, which flows into the left atrium, and cutaneous veins, carrying blood through the vena cava system into the right atrium). This determines the need for mixing both blood flows in the ventricle of the heart and the impossibility of efficient separation of arterial and venous blood. As a result, it is impossible for amphibians to develop effective systems of thermoregulation and a high level of metabolism; the achievement of homeothermy for amphibians is prohibited.
Obviously, the evolution of the respiratory system of amphibians can be interpreted as an example of an inadaptive version of evolutionary transformations, according to V.O. Kovalevsky. In the organization of amphibians, the imperfect mode of ventilation of the lungs has proven to be a key evolutionary prohibition for the development of important adaptations in many dependent systems of the body.
But often a very perfect adaptation itself can play the role of a key prohibition in relation to the development of certain adaptations of other body systems. A spectacular example of this kind is provided by cascade relationships in the organization of insects, also determined by the characteristics of their respiratory system. The respiratory organs of insects are formed by a complex system of tracheas - branched air tubes that permeate the entire body; the thinnest tracheal stems reach almost all cells. According to M.S. Gilyarov, it was the perfection of the tracheal system that allowed insects to master a wide range of terrestrial habitats under conditions of moisture deficit. At the same time, the tracheal system created the prerequisites for a significant intensification of gas exchange, up to the achievement of temporary homeothermia in some insect species during flight.
On the other hand, as shown by V.N. Beklemishev, the tracheal system in a certain way limits the adaptive and evolutionary capabilities of insects, leaving an imprint on their entire organization. Extremely branched trachea make it unnecessary for the circulatory system to participate in gas exchange, and its peripheral parts are largely reduced. But with such an arrangement of the respiratory and transport systems, the supply of massive organs is difficult, which limits the possibilities of increasing the size of the body. The vast majority of insects are small (in large modern species of beetles, stick insects, dragonflies, the body length does not exceed 13-15 cm, only in some tropical stick insects it reaches 26 cm). The "evolutionary experiments" of insects in the field of large forms were unsuccessful: the largest known insects, the meganeurous dragonflies, reaching about 70 cm in wingspan with a body length of about 30 cm, died out in the early Permian time.
Thus, in insects, the specific features of the distribution and respiratory systems became the reason for the emergence of an evolutionary prohibition on increasing body size. Small body sizes, in turn, determine many features of the organization, behavior and ecology of insects, which have reached high perfection in the "world of small forms". Small body size limits the number of cells in the body, particularly in the central nervous system. Insects are characterized by autonomization of the peripheral parts of the nervous system (closure of reflex arcs at the level of peripheral ganglia) and the predominance of hereditarily fixed automated forms of behavior. The tracheal system also limits the possibilities of ecological expansion of insects: with a huge variety of forms and adaptation, insects were completely unable to master the most ancient and extensive environment of life - the seawater column. This is probably due to the high buoyancy of the insect body, penetrated by a dense network of air passages.
Reasons for parallel evolution
Obviously, species descending from a common ancestor and retaining homologous genes, morphogenetic systems, and phenotypic structures should for these reasons have significant similarities in the organismic factors directing the evolution. The natural result of this is the widespread occurrence of the phenomena of parallel evolution of related phyletic lineages, known as one of the manifestations of the direction of phylogenesis. At the same time, as we have already noted, gene homology is of significant importance only for closely related species, while the parallel evolution of taxa of a higher rank is determined primarily by the similarity of morphogenetic and morphophysiological factors.
The long parallel evolution of independent phylogenetic stems is greatly facilitated by the cascade interactions between organ systems inherited from common ancestors. Changes in the key system affect the state of the entire cascade of systems dependent on it, creating prerequisites for certain directions of evolutionary transformations and prohibiting others. After the formation of any key adaptation, adaptive radiation begins. The related phyletic lineages that have arisen in this case inherit, together with the key trait, the entire complex of systemic interrelationships caused by them and, accordingly, the entire set of evolutionary potencies, i.e. possible directions of evolutionary changes and evolutionary prohibitions. An inevitable consequence of this is the emergence of parallel evolutionary transformations in systems of the organism dependent on the key trait in related phyletic lineages.
Thus, the historically established organization of this taxon limits the choice of possible directions of evolution for its constituent species to a certain framework. If natural selection for a long time favors the development of any category of adaptation (for example, food processing by the jaws of predators eating large prey, as in the ancestors of mammals), the direction of evolutionary transformations in the bundle of related phyletic lines receives, so to speak, "double support" - with sides of both organismic and extraorganic factors. This is the reason for the emergence of stable evolutionary trends and the parallel evolution of independent lineages in the phylogenesis of many groups of organisms.
One of the most important manifestations of the direction of macroevolution is the progressive nature and wide spread of evolutionary transformations along the path of morphophysiological progress. We will look at evolutionary progress and related problems in the next chapter.
CHAPTER 4. EVOLUTIONARY PROGRESS
Evolutionary progress is one of the central problems of the theory of evolution, which is of fundamental general biological and ideological significance, being closely related to understanding the direction of the evolution of life and the place of man in nature. At the same time, the problem of evolutionary progress is one of the most confusing. Even in the very concept of "evolutionary progress" different scientists often put different content, using it to denote either the general complication and improvement of the organization, or the achievement of biological prosperity by a given group of organisms, or a certain sequence of evolutionary transformations in a given direction (for example, during the development of any devices). In this regard, some researchers even believe that the concept of progress is subjective and anthropocentric, i.e. artificially puts a person at the top of the evolution of organisms.
However, an unbiased review of the general picture of the development of life on Earth convincingly proves the reality of the gradual complication and improvement of organization that took place in the history of many groups of organisms. Evolution is "from simple to complex" and is designated by most scientists as evolutionary progress.
The foundations of modern concepts of evolutionary progress were laid by A.N. Severtsov, who pointed out, first of all, the need to distinguish between the concepts of biological and morphophysiological progress. Under biological progress the success of a given group of organisms in the struggle for existence is understood, no matter how this success is achieved. Biological progress is manifested in an increase in the number of individuals of a given taxon, expansion of the area of its geographical distribution, and breakdown into taxa of a lower rank (adaptive radiation). Accordingly, biological regression, characterized by opposite indicators, means the failure of this group of organisms in the struggle for existence.
On the other side, morphophysiological progress represents an evolutionary complication and improvement of an organization. From the standpoint of a systems approach, morphophysiological progress is characterized as a process of qualitative transformation of biological systems in the direction from less organized forms to more organized ones.
According to A. N. Severtsov, morphophysiological progress is one of the possible paths (along with other main directions of evolution identified by him) for achieving biological progress. The evolutionary "choice" of one or the other of these paths is determined by the relationship between the characteristics of the organization of a given group, its way of life and the nature of changes in environmental conditions.
Criteria for morphophysiological progress
A.N. Severtsov linked morphophysiological progress with an increase in differentiation of the organism and intensification of functions(in particular, with an increase in the intensity of metabolic processes and the energy of the body's vital activity). Later, various scientists (I.I.Shmalgauzen, B.Rensch, D.Huxley, K.M. Zavadsky, A.P. Rasnitsyn) added others to these two criteria of arogenesis. The most important of these are: improvement integration organism; rationalization its structure, that is, streamlining the organization leading to optimized functioning; level up homeostasis, i.e. the ability to maintain the constancy of the internal environment of the body; increasing the amount of information extracted by the body from the external environment, and improving its processing and use. Other criteria for arogenesis, proposed by different scientists, are either partial derivatives of the listed main criteria, or do not always correlate with morphophysiological progress. The specific manifestations of morphophysiological progress in different phylogenetic stems differ significantly in accordance with the historically established features of the organization of different groups and the different nature of relationships with the external environment. Therefore, it is often difficult to compare the levels of morphophysiological progress achieved by different groups. Charles Darwin even believed that "attempts to compare in terms of the height of the organization of representatives of different types are completely hopeless; who decides who is taller, a cuttlefish or a bee" 2. Indeed, the methods for quantifying the height of an organization have not yet been developed for such comparisons. However, at a qualitative level, a comparison according to the main criteria of arogenesis is still possible: there can hardly be any doubt that the general level of organization of insects is higher than, for example, in millipedes, and in any arthropods it is higher than in annelids, and in the latter it is higher. than flatworms, etc.
At the same time, it is important to emphasize that only the totality of the named main criteria, at least four of them, characterizes general morphophysiological progress (arogenesis), i.e. increasing the organization in phylogeny of this group of organisms. Arogenesis took place, for example, in the phylogenesis of vertebrates, arthropods, molluscs; among taxa of a lower rank, general arogenesis is characteristic of mammals, birds, insects, and cephalopods.
At the same time, in many phylogenetic stems, progressive changes occurred only according to certain basic criteria. So, for example, the jaw apparatus of snakes is much more complexly differentiated and more perfectly integrated than that of their ancestors - lizards. In snakes, it includes significantly more movable bone elements and muscles serving these movements than in lizards. This is due to the adaptation of snakes to swallowing large prey whole - in the process of swallowing, the left and right halves of the upper and lower jaws can move independently, as if "stepping" over the body of the victim and gradually enveloping the swallowed object further and further, and the bones of the snake jaws diverge somewhat from each other. friend, held by strong and elastic ligaments. However, this undoubted complication and improvement of the jaw apparatus of snakes in comparison with lizards still cannot be regarded as a manifestation of general morphophysiological progress, since in their importance for the organism as a whole, these evolutionary achievements are of a particular nature: the general level of organization of snakes is not higher than that of lizards. This is evidenced by the level of their energy and metabolic processes, and the similarity of homeostasis, receptor systems, higher nervous activity, etc.
Even such an important manifestation of the general intensification of the body's functions as an increase in the level of metabolic and energy processes can occur in isolation from other aspects of morphophysiological progress, and in this case in itself does not lead to a general increase in the level of organization. So, among crustaceans, the most intensive metabolism is possessed by shtitti (Triops cancriformis), which retain a primitive and very conservative organization - these crustaceans are one of the examples of persistent forms, since their structure has not undergone noticeable changes since the Triassic period (i.e. about 200 million years ).
For situations where the improvement of the organization occurs only according to individual criteria, it is advisable to use the terms private progress(proposed by A.L. Takhtadzhyan) and adaptive progress(N.V. Timofeev-Resovsky and others). Depending on the degree of influence of the arising changes on the organism as a whole and on the latitude of the adaptations being formed, a particular progress corresponds either to epectogenesis (the development of epecto-morphoses, similar to the apparatus of locomotion and the kinetic skull of snakes), or to allogenesis (the development of allomorphoses: poisonous glands in snakes, various types dental system in different groups of mammals, etc.).
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Hereditary variability
Accidental (undirected) retention of signs
Population waves- periodic fluctuations in the size of the population. For example: the number of hares is not constant, every 4 years there are a lot of them, then a decline in numbers follows. Meaning: During a recession, genes drift.
Gene drift: if the population is very small (due to a catastrophe, illness, recession of the pop-wave), then the signs persist or disappear, regardless of their usefulness, by accident.
Struggle for existence
Cause: many more organisms are born than can survive, so there is not enough food and territory for all of them.
Definition: a set of relationships between an organism and other organisms and the environment.
Forms:
- intraspecific (between individuals of the same species),
- interspecific (between individuals of different species),
- with environmental conditions.
Corollary: natural selection
Natural selection
This is the main, leading, directing factor of evolution, leads to adaptation, to the emergence of new species.
Insulation
Gradual accumulation of differences between populations isolated from each other can lead to the fact that they cannot interbreed - there will be biological isolation, two different views will appear.
Isolation / speciation types:
- Geographic - if there is an insurmountable barrier between the populations - a mountain, a river, or a very long distance (arises with a rapid expansion of the area). For example, Siberian larch (in Siberia) and Daurian larch (in the Far East).
- Ecological - if two populations live in the same territory (within the same range), but cannot interbreed. For example, different populations of trout live in Lake Sevan, but go to spawn in different rivers flowing into this lake.
Insert in the text "Fluctuations in the number of individuals" the missing terms from the proposed list, using numbers for this. The number of individuals in populations is variable. Its periodic oscillations are called (A). Their importance for evolution lies in the fact that with an increase in the population size, the number of mutant individuals increases as many times as the number of individuals increased. If the number of individuals in a population decreases, then its (B) becomes less diverse. In this case, as a result of (C), individuals with certain (D) may disappear from it.
1) population wave
2) the struggle for existence
3) variability
4) gene pool
5) natural selection
6) genotype
7) phenotype
8) heredity
Answer
Choose the one that is most correct. Combinative variability is referred to as
1) driving forces of evolution
2) directions of evolution
3) the results of evolution
4) stages of evolution
Answer
1. Establish the sequence of the formation of adaptations in the plant population in the process of evolution. Write down the corresponding sequence of numbers.
1) consolidation of a new trait by stabilizing selection
2) the effect of the driving form of selection on individuals of the population
3) change in the genotypes of individuals of the population in new conditions
4) changing the conditions of the population's habitat
Answer
2. Establish the sequence of formation of plant fitness in the process of evolution. Write down the corresponding sequence of numbers.
1) breeding individuals with beneficial changes
2) the emergence of various mutations in the population
3) the struggle for existence
4) preservation of individuals with hereditary changes useful for given environmental conditions
Answer
3. Establish the sequence of microevolutionary processes. Write down the corresponding sequence of numbers.
1) the action of driving selection
2) the emergence of beneficial mutations
3) reproductive isolation of populations
4) the struggle for existence
5) the formation of a subspecies
Answer
4. Establish the sequence of actions of the driving forces of evolution. Write down the numbers under which they are indicated.
1) the struggle for existence
2) breeding individuals with beneficial changes
3) the appearance in the population of various hereditary changes
4) preservation of predominantly individuals with hereditary changes useful in the given environmental conditions
5) the formation of adaptability to the environment
Answer
5. Establish the sequence for the formation of the population of the dark-colored moth moth in polluted industrial areas.
1) the appearance in the offspring of multi-colored butterflies
2) an increase in the number of butterflies with a darker color
3) preservation as a result of natural selection of butterflies with a dark color and death with a light
4) the emergence of a population of dark-colored butterflies
Answer
6n. Establish a sequence of processes for speciation. Write down the corresponding sequence of numbers.
1) the spread of useful traits in isolated populations
2) natural selection of individuals with useful traits in isolated populations
3) rupture of the species range due to changes in the relief
4) the emergence of new traits in isolated populations
5) the formation of new subspecies
Answer
1. Indicate the sequence of the processes of geographic speciation. Write down the corresponding sequence of numbers
1) the spread of the trait in the population
2) the appearance of mutations in new living conditions
3) spatial isolation of populations
4) selection of individuals with useful changes
5) the formation of a new type
Answer
2. Determine the sequence of processes characteristic of geographic speciation
1) the formation of a population with a new gene pool
2) the emergence of a geographical barrier between populations
3) natural selection of individuals with characteristics adaptive to these conditions
4) the emergence of individuals with new traits in an isolated population
Answer
3. Indicate the sequence of processes in geographic speciation
1) accumulation of mutations in new conditions
2) territorial isolation of the population
3) reproductive isolation
4) the formation of a new type
Answer
4. Indicate the sequence of stages of geographic speciation
1) divergence of traits in isolated populations
2) reproductive isolation of populations
3) the emergence of physical barriers in the range of the original species
4) the emergence of new species
5) the formation of isolated populations
Answer
5. Establish the sequence of stages of geographic speciation. Write down the corresponding sequence of numbers.
1) the appearance in populations of new random mutations
2) territorial isolation of one population of the species
3) change in the gene pool of the population
4) preservation by natural selection of individuals with new traits
5) reproductive isolation of populations and the formation of a new species
Answer
Establish the sequence of stages of ecological speciation. Write down the corresponding sequence of numbers.
1) ecological isolation between populations
2) biological (reproductive) isolation
3) natural selection in new environmental conditions
4) the emergence of ecological races (ecotypes)
5) the emergence of new species
6) development of new ecological niches
Answer
Choose the one that is most correct. With ecological speciation, as opposed to geographic, a new species appears
1) as a result of the disintegration of the original area
2) inside the old area
3) as a result of the expansion of the original area
4) due to gene drift
Answer
Choose the one that is most correct. An evolutionary factor contributing to the accumulation of various mutations in the population is
1) intraspecific struggle
2) interspecies struggle
3) geographic isolation
4) limiting factor
Answer
Choose the one that is most correct. Hereditary variability in the process of evolution
1) fixes the created feature
2) is the result of natural selection
3) supplies material for natural selection
4) selects adapted organisms
Answer
Choose the one that is most correct. An example of ecological speciation
1) Siberian and Daurian larch
2) white hare and brown hare
3) European and Altai squirrel
4) populations of Sevan trout
Answer
Choose three correct answers out of six and write down the numbers under which they are indicated. Indicate the signs that characterize natural selection as a driving force of evolution
1) Source of evolutionary material
2) Provides a reserve of hereditary variability
3) The object is the phenotype of the individual
4) Provides selection of genotypes
5) Directional factor
6) The factor of random action
Answer
1. Establish a correspondence between the process occurring in nature and the form of the struggle for existence: 1) intraspecific, 2) interspecific
A) the competition between individuals of the population for the territory
B) the use of one type by another
C) rivalry between individuals for a female
D) displacement of a black rat by a gray rat
D) predation
Answer
2. Establish a correspondence between the example of the struggle for existence and the form to which this struggle belongs: 1) intraspecific, 2) interspecific. Write down the numbers 1 and 2 in the correct order.
A) determination of nesting sites in the forest with crossbills
B) the use of cattle by bovine tapeworm as a habitat
C) rivalry between males for dominance
D) displacement of a black rat by a gray rat
E) fox hunting for vole mice
Answer
3. Establish a correspondence between examples and types of struggle for existence: 1) intraspecific, 2) interspecific. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) displacement of a black rat by a gray rat
B) the behavior of male moose during the mating season
C) fox hunting for mice
D) the growth of beet seedlings of the same age in the same bed
E) behavior of a cuckoo in the nest of another bird
E) rivalry of lions in the same pride
Answer
4. Establish a correspondence between the processes occurring in nature and the forms of the struggle for existence: 1) interspecific, 2) intraspecific. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) marking the territory with a male field mouse
B) mating of male wood grouses in the forest
C) oppression of seedlings of cultivated plants by weeds
D) competition for light between spruce trees in the forest
D) predation
E) displacing the black cockroach with a redhead
Answer
1. Establish a correspondence between the cause of speciation and its way: 1) geographical, 2) ecological. Write down the numbers 1 and 2 in the correct order.
A) expansion of the range of the original species
B) stability of the range of the original species
C) division of the species range by various barriers
D) variety of variability of individuals within the range
E) diversity of habitats within a stable range
Answer
2. Establish a correspondence between the features of speciation and their methods: 1) geographical, 2) ecological. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) isolation of populations due to a water barrier
B) isolation of populations due to different periods of reproduction
C) isolation of populations due to the emergence of mountains
D) isolation of populations due to large distances
E) isolation of populations within the range
Answer
3. Establish a correspondence between mechanisms (examples) and methods of speciation: 1) geographical, 2) ecological. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) expansion of the range of the original species
B) preservation of a single original range of the species
C) the appearance of two species of gulls in the North and Baltic seas
D) the formation of new habitats within the original range
E) the presence of populations of Sevan trout, differing in terms of spawning
Answer
4. Establish a correspondence between the characteristics and methods of speciation: 1) geographical, 2) ecological. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) long-term constancy of the existence of the range of the original species
B) division of the range of the original species by an insurmountable obstacle
C) different food specialization within the original area
D) division of the area into several isolated parts
E) development of various habitats within the original area
E) isolation of populations due to different periods of reproduction
Answer
5. Establish a correspondence between the characteristics and methods of speciation: 1) geographical, 2) ecological. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) stability of the area
B) the emergence of physical barriers
C) the emergence of populations with different breeding times
D) isolation of populations in the forest by road
D) expansion of the area
Answer
1. Choose from the text three sentences that describe the ecological mode of speciation in the evolution of the organic world. Write down the numbers under which they are indicated. (1) Reproductive isolation causes microevolution. (2) Free interbreeding ensures the exchange of genes between populations. (3) Reproductive isolation of populations can occur within the same area for various reasons. (4) Isolated populations with different mutations adapt to the conditions of different ecological niches within the former range. (5) An example of such speciation is the formation of buttercup species that have adapted to life in the field, in the meadow, in the forest. (6) The species serves as the smallest genetically stable supraorganism system in living nature.
Answer
2. Read the text. Choose three sentences that indicate ecological speciation processes. Write down the numbers under which they are indicated. (1) During speciation, the species range is divided into fragments. (2) There are several populations in Lake Sevan that differ in terms of spawning. (3) Speciation may be associated with a change in the ecological niche of a species. (4) If polyploid forms are more viable than diploid forms, they can give rise to a new species. (5) In Moscow and the Moscow region, there are several species of tits, differing in the methods of obtaining food.
Answer
3. Read the text. Select three sentences that describe ecological speciation. Write down the numbers under which they are indicated. (1) A species in nature exists in the form of separate populations. (2) Due to the accumulation of mutations, a population can be formed under changed conditions in the original area. (3) Sometimes microevolution is associated with a gradual expansion of the range. (4) Natural selection fixes persistent differences between plants of different populations of the same species, occupying the same area, but growing in a dry meadow or in a river floodplain. (5) For example, this is how the species of buttercups were formed that grow in the forest, in the meadow, along the banks of rivers. (6) The spatial isolation caused by mountain building may be a factor in speciation.
Answer
4. Read the text. Select three sentences that describe ecological speciation. Write down the numbers under which they are indicated. (1) Speciation can occur within the same continuous range if organisms inhabit different ecological niches. (2) The reasons for speciation are the mismatch of the timing of reproduction in organisms, the transition to new food without changing the habitat. (3) An example of speciation is the formation of two subspecies of the great rattle growing in the same meadow. (4) Spatial isolation of groups of organisms can occur when the range expands and the population gets into new conditions. (5) As a result of adaptations, the South Asian and Eurasian subspecies of the great tit were formed. (6) As a result of isolation, endemic island species of animals have formed.
Answer
5. Read the text. Choose three sentences that fit the description of ecological speciation. Write down the numbers under which they are indicated. (1) The result of the action of the driving forces of evolution is the spread of the species to new areas. (2) Speciation may be related to the expansion of the range of the original species. (3) Sometimes it occurs as a result of the rupture of the original range of a species by physical barriers (mountains, rivers, etc.) (4) New species can master specific living conditions. (5) As a result of food specialization, several species of tits have been formed. (6) For example, the great tit feeds on large insects, and the crested tit feeds on the seeds of conifers.
Answer
1. Read the text. Select three sentences that describe features of geographic speciation. Write down the numbers below which the selected statements are indicated. (1) Associated with spatial isolation due to the expansion or dismemberment of the area, as well as human activities. (2) Occurs in the case of a rapid increase in the chromosomal set of individuals under the influence of mutagenic foctors or in case of errors in the process of cell division. (3) More common in plants than animals. (4) Occurs by settling individuals into new territories. (5) In different habitats, ecological races are formed, which become the ancestors of new species. (6) Polyploid viable forms can give rise to a new species and completely displace the diploid species from the range.
Answer
2. Choose from the text three sentences that characterize the geographic mode of speciation in the evolution of the organic world. Write down the numbers under which they are indicated. (1) The exchange of genes between populations during the reproduction of individuals preserves the integrity of the species. (2) In the event of reproductive isolation, crossing becomes impossible and the population embarks on the path of microevolution. (3) Reproductive isolation of populations occurs when physical barriers arise. (4) Isolated populations expand their range by maintaining adaptations to new living conditions. (5) An example of such speciation is the formation of three subspecies of the great tit, which have mastered the territories of eastern, southern and western Asia. (6) The species serves as the smallest genetically stable supraorganism system in living nature.
Answer
3. Read the text. Select three sentences that describe geographic speciation. Write down the numbers under which they are indicated. (1) Speciation is the result of natural selection. (2) One of the reasons for speciation is the mismatch of the reproduction time of organisms and the occurrence of reproductive isolation. (3) An example of speciation is the formation of two subspecies of the great rattle growing in the same meadow. (4) Spatial isolation of groups of organisms may be accompanied by an expansion of the range, in which populations find themselves in new conditions. (5) As a result of adaptations, the South Asian and Eurasian subspecies of the great tit were formed. (6) As a result of isolation, endemic island species of animals have formed.
Answer
4. Read the text. Select three sentences that describe geographic speciation. Write down the numbers under which they are indicated. (1) A species in nature occupies a certain area and exists in the form of separate populations. (2) Due to the accumulation of mutations, a population with a new gene pool can be formed within the original range. (3) Expansion of the species range leads to the emergence of isolated new populations at its borders. (4) In the new boundaries of the range, natural selection reinforces persistent differences between spatially disunited populations. (5) Free crossing is disturbed between individuals of the same species as a result of mountain barriers. (6) Speciation is gradual.
Answer
Choose three correct answers out of six and write down the numbers under which they are indicated. The processes leading to the formation of new species in nature include
1) mitotic cell division
2) an abrupt mutational process
4) geographic isolation
5) asexual reproduction of individuals
6) natural selection
Answer
Establish a correspondence between the example and the way of speciation, which this example illustrates: 1) geographical, 2) ecological. Write down the numbers 1 and 2 in the correct order.
A) the habitation of two populations of common perch in the coastal zone and at a great depth of the lake
B) the habitation of different populations of the blackbird in deep forests and near human habitation
C) disintegration of the range of May lily of the valley into isolated areas due to glaciation
D) education of different types of tits based on food specialization
E) the formation of Daurian larch as a result of the expansion of the range of Siberian larch to the east
Answer
Choose three options. What evolutionary factors influence the process of ecological speciation?
1) modification variability
2) fitness
3) natural selection
4) mutational variability
5) struggle for existence
6) convergence
Answer
Choose three options. What factors are the driving forces of evolution?
1) modification variability
2) mutation process
3) natural selection
4) the adaptability of organisms to the environment
5) population waves
6) abiotic environmental factors
Answer
1) crossing over
2) mutation process
3) modification variability
4) insulation
5) variety of species
6) natural selection
Answer
Choose three options. The driving forces of evolution include
1) isolation of individuals
2) the adaptability of organisms to the environment
3) variety of species
4) mutational variability
5) natural selection
6) biological progress
Answer
Read the text. Choose three sentences that indicate the driving forces behind evolution. Write down the numbers under which they are indicated. (1) The synthetic theory of evolution states that species live in populations in which evolutionary processes begin. (2) It is in populations that the most acute struggle for existence is observed. (3) As a result of mutational variability, new characters gradually appear. Including adaptation to environmental conditions - idioadaptation. (4) This process of the gradual appearance and maintenance of new traits under the influence of natural selection, leading to the formation of new species, is called divergence. (5) The formation of new large taxa occurs through aromorphoses and degeneration. The latter also leads to the biological progress of organisms. (6) Thus, the population is the initial unit in which the main evolutionary processes take place - a change in the gene pool, the emergence of new characters, the emergence of adaptations.
Answer
Establish a correspondence between the factors of speciation and its mode: 1) geographical, 2) ecological, 3) hybridogenic. Write down the numbers 1-3 in the correct order.
A) polyploidization of hybrids from closely related crossing
B) differences in habitats
C) division of the area into fragments
D) the habitation of different types of lily of the valley in Europe and the Far East
E) food specialization
Answer
Analyze the "Struggle for Existence" table. For each letter cell, select the appropriate term from the list provided. Write down the selected numbers, in the order corresponding to the letters.
1) dealing with environmental conditions
2) limited natural resources
3) fight against unfavorable conditions
4) various ecological criteria of the species
5) seagulls in colonies
6) males during the mating season
7) birch and tinder fungus
8) the need to choose a sexual partner
Answer
Choose the one that is most correct. The division of populations of the same species according to the timing of breeding can lead to
1) population waves
2) convergence of features
3) increased interspecies struggle
4) ecological speciation
Answer
Select two sentences that indicate processes that are NOT related to the intraspecific struggle for existence. Write down the numbers under which they are indicated.
1) Competition between wolves of the same population for prey
2) Fight for food between gray and black rats
3) Destruction of young animals in case of excess population
4) Struggle for supremacy in a pack of wolves
5) leaf reduction in some desert plants
Answer
© D.V. Pozdnyakov, 2009-2019
Charles Darwin (1809-1882) House in Shrewsbury
(England), where Ch.
Darwin
Charles Darwin's father
Robert Waring Darwin
Charles Darwin's mother
Susanna Darwin
in the family of a doctor. While studying in
Universities of Edinburgh and Cambridge
Darwin gained in-depth knowledge of
zoology, botany and geology, skills and
taste for field research. Big
role in shaping its scientific
worldview was played by the book of an outstanding
English geologist Charles Lyell
"Principles of Geology". The decisive turn in his fate was
round the world trip on the ship "Beagle"
(1832-1837). According to Darwin himself, in
during this trip they made him
strongest impression: “1) discovery
giant fossil animals that
were covered with a carapace similar to a carapace
modern battleships; 2) then
the fact that as we move along
mainland South America closely related
animal species replace one another; 3) one
the fact that closely related species of different
islands of the Gallapagos archipelago
differ slightly from each other. It was
it is obvious that this kind of facts, as well as
many others, could only be explained
based on the assumption that the species
gradually changed, and this problem became
Chase me".
Voyage around the world on the ship "Beagle" 1831-1836
Darwin Returns From Around The Worldtravel staunch supporter
views on species variability
Preconditions for the emergence of Charles Darwin's theory
1. Discoveries in biologycellular structure of organisms - R. Hooke,
A. Levenguk
similarity of animal embryos - K. Baer
discoveries in comparative anatomy
and paleontology - J. Cuvier
2. Works of the geologist C. Lyell on evolution
the surface of the earth under the influence
natural causes (t, wind, precipitation, etc.)
3. Development of capitalism, agriculture,
breeding
4. Creation of animal breeds and plant varieties
5.1831-1836 - travel around the world
Beagle
The Importance of Artificial Selection in the Creation of Darwin's Theory
Artificial selection is the process of creating newbreeds (varieties) by systematic selection and
reproduction of individuals with valuable for humans
signs
From the analysis of the huge material on the creation
breeds and varieties Darwin learned the principle
artificial selection and based on it
created his own evolutionary teaching
individuals selected by humans for reproduction,
will pass on their traits to descendants (heredity)
the variety of descendants is explained by different
combinations of traits from parents and mutations
(hereditary (Darwin's uncertain)
variability)
The creative role of artificial selection
Artificial selection leads to changean organ or sign of interest to a person
Artificial selection leads to discrepancy
characteristics: members of the breed (variety) more and more
become more unlike the wild
Artificial selection and hereditary
variability is the main driving force in
formation of breeds and varieties
Forms of artificial selection
Unconscious selection is a selection in whichthere is no goal of creating a new variety or breed.
People keep the best, in their opinion, individuals and
destroy (reject) the worst (more milk-producing
cows, best horses)
Methodical selection is selection,
carried out by a person according to a certain plan,
for a specific purpose - to create a breed or variety
Creation of evolutionary theory
1842 - the beginning of work on the book"Origin of Species"
1858 - A. Wallace, being in
travel in Malay
archipelago, wrote an article "About
aspiration of varieties to
unlimited deviation from
original type ", in which
contained theoretical
provisions similar to
Darwinian.
1858 - Charles Darwin received from A.R.
Charles Darwin
(1809-1882, England)
Alfred Wallace
(1823-1913, England)
Creation of evolutionary theory
1858 - July 1 at a special meetingLinnean Society were outlined
the concepts of Charles Darwin and A. Wallace about
the emergence of species by natural
selection
1859 - the first edition of the book "Origin
species ", 1250 copies
All creatures have a certain
level of individual variability
Signs from parents are passed on
descendants by inheritance
Each type of organism is capable of
unlimited reproduction (in
a box of poppy seeds, 3000 seeds, the elephant for
all life brings up to 6 elephants, but
offspring of 1 pair in 750 years = 19 million
individuals)
Lack of vital resources
leads to a struggle for existence
They survive in the struggle for existence
best fit for data
conditions of the individual
Darwin's concept of natural selection
Evolutionary Material - Uncertain VariabilityNatural selection is a consequence of the struggle for
Existence
Forms of struggle for
Existence
Intraspecific
(between
individuals
one kind)
Interspecific
(between
individuals
different types)
Fight against
unfavorable
conditions (t,
lack of water and
food, etc.)
Driving forces of evolution according to Darwin
Hereditary variabilityStruggle for existence
Natural selection
Natural selection is the main driving force behind evolution
The result of natural selectionAdaptation,
providing
th survival
and
reproduced
no offspring
Divergence -
gradual
divergence
groups of individuals by
a separate
featured and
education
new species So, the idea of the origin of species by natural selection arose from
Darwin in 1838. He worked on it for 20 years. In 1856 on the advice of Lyell
he began to prepare his work for publication. In 1858, young English
scientist Alfred Wallace sent Darwin the manuscript of his article “On the tendency
varieties to unlimited deviation from the original type. " This
the article contained a statement of the idea of the origin of species by natural
selection. His idea of evolution met with passionate support from some scientists and
harsh criticism of others. This and subsequent works of Darwin "Changes
animals and plants during domestication "," The origin of man and sexual
selection "," Expression of emotions in humans and animals "immediately after release
translated into many languages. It is noteworthy that the Russian translation of the book
Darwin's "Changes in animals and plants during domestication" was
published earlier than its original text.
Natural selection is the only factor that determines the direction of the evolutionary process, the adaptation of organisms to a particular habitat. Due to selection, individuals with useful mutations, that is, appropriate to the habitat, are preserved and reproduced in the population. Individuals less adapted to their habitat die or survive, but their offspring are few.
The genotypes of individuals in the population are different, and the frequency of their occurrence is also different. The selection efficiency depends on the manifestation of the trait in the genotype. The dominant allele immediately manifests itself phenotypically and is subjected to selection. The recessive allele is not selected until it is homozygous. I.I.Shmalgauzen distinguished two main forms of natural selection: driving and stabilizing.
Driving selection
Driving selection leads to the elimination of individuals with old traits that do not correspond to the changed habitat, and the formation of a population of individuals with new traits. Is it happening in a slowly changing environment? habitat.
An example of the action of motive selection is the change in the color of the wings of a moth moth. The butterflies inhabiting the tree trunks were predominantly light in color, invisible against the background of light lichens covering the tree trunks.
From time to time, dark-colored butterflies appeared on the trunks, which were clearly visible and destroyed by birds. Due to the development of industry and air pollution with soot, lichens disappeared and darkened tree trunks were exposed. As a result, light-colored butterflies, clearly visible against a dark background, were destroyed by birds, and dark-colored individuals were preserved by selection. After some time, most butterflies in populations near industrial centers turned dark.
What is the driving selection mechanism?
The genotype of the birch moth contains genes that determine the dark and light coloration of butterflies. Therefore, both light and dark butterflies appear in the population. The prevalence of certain butterflies depends on the environmental conditions. In some environmental conditions, predominantly dark-colored individuals remain, while in others, light-colored individuals with different genotypes are preserved.
The mechanism of motive selection consists in the preservation of individuals with useful deviations from the previous norm of reaction and the elimination of individuals with the previous norm of reaction.
Stabilizing selection
Stabilizing selection preserves the individuals with the reaction rate established under the given conditions and eliminates all deviations from it. It works if the environmental conditions do not change for a long time. So, the flowers of the snapdragon plant are pollinated only by bumblebees. The size of the flower corresponds to the size of the body of bumblebees. All plants with very large or very small flowers are not pollinated and do not form seeds, that is, they are eliminated by stabilizing selection.
The question arises: are all mutations eliminated by selection?
It turns out that not all. Selection eliminates only those mutations that manifest phenotypically. In heterozygous individuals, recessive mutations persist, which do not appear outwardly. They serve as the basis for the genetic diversity of the population.
Observations and experiments testify to the fact that selection actually occurs in nature. For example, observations have shown that predators most often destroy individuals with some kind of defect.
Scientists have conducted experiments to study the effects of natural selection. Caterpillars of different colors - green, brown, yellow - were placed on a green board. The birds primarily pecked at the yellow and brown caterpillars visible against the green background.
67. The decline in the number and range of the Ussuri tiger is an example of: 1) biological regression 2) degeneration 3) biological progress 4) aromorphosis68. A dog breed is: 1) genus 2) species 3) natural population 4) artificial population69. Selection, leading to a shift in the average norm of the indicator of a trait, is called: 1) artificial 2) disruptive 3) driving 4) stabilizing70. Microevolution results in: 1) geographical isolation 2) reproductive isolation 3) hereditary variability 4) modification variability71. Degeneration: 1) always leads to the extinction of the species 2) never leads to biological progress 3) can lead to biological progress 4) leads to complication of the overall organization72. The guiding factor of evolution is: 1) heredity 2) variability 3) mutation 4) natural selection73. Evolutionary processes occurring in populations that lead to the emergence of new species are called: 1) microevolution 2) macroevolution 3) interspecific struggle 4) intraspecific struggle74. Loss of vision in animals living underground is an example of: 1) aromorphosis 2) idioadaptation 3) degeneration 4) biological regression75. The material for natural selection is: 1) hereditary variability 2) modification variability 3) adaptation of populations to the environment 4) diversity of species76. Fitness is the result of: 1) modification variability 2) natural selection and conservation of individuals with useful traits 3) an increase in the number of homozygotes in a population 4) closely related crossing
The task contains questions, for each of which several answers are given; among them, only one is the faithful one.1. The leading role in evolution is played by:
a - mutational variability;
b - modification variability;
c - group variability;
d - non-hereditary variability.
2. The main criterion for the type is:
a - physiological;
b - geographical;
в - ecological;
d - all these criteria
3. More than one nucleus can occur in cells:
a - protozoa;
b - muscles;
c - connective tissue;
d - all answers are correct.
4. The successive decrease in the number of fingers in the ancestors of the horse is an example:
a - homologous series;
b - phylogenetic series;
c - aromorphosis;
d - convergence.
5. Microevolution leads to the formation of new:
a - family groups;
b - subspecies and types;
c - childbirth;
d - classes.
6. Morgan's Law concerns:
a - dihybrid crossing;
b - gamete purity;
c - incomplete dominance;
d - gene linkage.
7. The main amount of solar energy in the ocean stores:
a - phytoplankton;
b - zooplankton;
c - fish and marine mammals;
d - large bottom algae.
8. The number of nucleotides that fit into the ribosome is equal to:
a - one;
b - three;
At six o'clock;
g - nine.
9. Monkey-men include:
a - Cro-Magnon;
b - australopithecus;
c - pithecanthropus;
d - Neanderthal.
10. With dihybrid crossing, the number of phenotype classes in the second generation is equal to:
a - four;
b - nine;
c - sixteen;
d - not a single answer is correct.
Answers:
1) a.
2) d.
3) b.
4) b.
5 B.
6) d.
7)
8)
9)
10) c.
Task 2. The task contains questions, for each of which several answers are given; among them, the correct ones can be from zero to five.
1. What cellular organelles have DNA:
a - centriole;
b - vacuole;
c - mitochondria;
r - core;
e - lysosomes.
2. Which of the following cell structures have a double membrane:
a - vacuole;
b - mitochondria;
c - chloroplasts;
d - membrane of prokaryotes;
e - eukaryotic membrane;
e - core;
3. Heterotrophs include:
a - phytoplankton;
b - mushrooms;
c - birds;
d - bacteria;
d - conifers.
5. The unit of the evolutionary process is:
a - view;
b - a set of individuals;
c - population;
Task 3.
1). The genotype of an organism is: a) the external and internal signs of the organism that are manifested b) hereditary traits of the organism c) the ability of the organism tochanges d) transmission of a trait from generation to generation 2) G. Mendel's merit is to identify: a) the distribution of chromosomes among gametes during meiosis b) patterns of inheritance of parental traits c) study of linked inheritance d) identifying the relationship between genetics and evolution 3) Hybridological method G. Mendel is based on: a) interspecific crossing of pea plants; b) growing plants under different conditions; c) crossing of different varieties of peas, differing in certain characteristics; d) cytological analysis of the chromosome set. 4) .Analyzing crossing is carried out for: a) identifying the dominant allele b) in order to find out which allele is recessive c) breeding a pure line d) detecting the heterozygosity of the organism for a certain trait. 5) The significance of crossing over is: a) the independent distribution of genes across gametes b) the preservation of the diploid set of chromosomes c) the creation of new hereditary combinations d) maintaining the constancy of the genotypes of the organism 6) Differences in the size of the leaves of one tree is an example of variability: a) genotypic b) modification c) mutational d) combinative. 6) A) Mutations: __________________________________________________________________ B) Modifications: ______________________________________________________________ 1) the limits of variability fit into the reaction norm; 2) there are abrupt, abrupt changes in the genotype; 3) changes occur under the influence of the environment; 4) the degree of expression of qualitative features changes; 5) there is a change in the number of genes in the chromosome; 6) appears under similar environmental conditions in genetically similar organisms, i.e., it has a group character. 7). A) Somatic mutations: ___________________________________________________________ B) Generative mutations: ____________________________________________________________ 1) not inherited; 2) arise in gametes; 3) arise in the cells of the body; 4) are inherited; 5) have evolutionary significance; 6) have no evolutionary significance. 8) Choose three correct statements. The law of independent inheritance of traits is observed under the following conditions: 1) one gene is responsible for one trait; 2) one gene is responsible for several traits; 3) hybrids of the first generation must be homozygous; 4) first generation hybrids must be heterozygous; 5) the genes under study should be located in different pairs of homologous chromosomes; 6) the genes under study can be located in one pair of homologous chromosomes.
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